At one time I use to document the history of use of each of my guns but stopped doing so. I got lazy. My high round count guns and failures at the time I stopped documenting history in 2010 are:
XD40 SC- 6K (none)
Ruger Mark II- 22K (not a failure upgraded trigger job in 2010)
LCR .38- 925 (none)
Charter Arms .38- 1.3K (none) (1980 production bought used in 1990)
LCP- 856 (none)
S&W M&P 9- 2.1K (feed problem after 1.5K-polished ramp)
S&W M&P 40- 2.3k (none)
Mosin Nagant 91/30- 3.5K (none)
Glock G22- "3" rounds ( bought used and experienced a catastrophic failure, fired before going into full battery, in 2004)
Note: most of the above hand guns have had a minimum of 100 rounds per month fired with the exception of the Mark II that has had at least 10K thru it since June of 2010.

I think we should also include the history failure along with the ammo history as I have done.